1. Consists of shares beneficially owned as a result of reporting person's ownership of units in the Pioneer Natural Resources USA, Inc. 401(k)

2. This transaction was executed in multiple trades at prices ranging from $203.50 to $204.50. The price reported above reflects the weighted average sale price. The reporting person will provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

3. This transaction was executed in multiple trades at prices ranging from $204.52 to $204.84. The price reported above reflects the weighted average sale price. The reporting person will provide upon request to the SEC staff, the issuer or a security holder of the issuer full information regarding the number of shares and prices at which the transaction was effected.

Thomas J. Murphy, Attorney-in-Fact For Scott D. Sheffield

05/22/2014

** Signature of Reporting Person

Date

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person,
see
Instruction
4
(b)(v).